Effect of layers on the photocatalytic hydrogen evolution in Dion–Jacobson layered-tantalum perovskites

Abstract

Tantalum-based layered perovskites have always been an interesting topic in photocatalysis, but limited information has been reported in terms of their layer factor. In this work, we have synthesized Dion–Jacobson layered perovskites (A′[A_n−1Ta_nO_3n+1]) of LaTaO₄, KLaTa₂O₇, and KCa₂Ta₃O₁₀ with n = 1, 2, and 3, respectively. With the modification of 1 wt% Pt co-catalysts, the photocatalytic analysis showed that the performance order of these layered perovskites with different layers is KLaTa₂O₇ (n = 2) > KCa₂Ta₃O₁₀ (n = 3) ≫ LaTaO₄ (n = 1) with both methanol and NaI as the sacrificial agents. This suggested the importance of interlayer K⁺ for high photocatalytic performance. We further analyzed the layered perovskites in detail by BET, photoelectrochemical analysis, Mott–Schottky, and VB-XPS test. The combined results indicated that the positions of the conduction band are the dominant factors for the photocatalytic performance of tantalum-based Dion–Jacobson layered perovskites with n = 2 and 3. This work sheds new light on the field of layered perovskites as efficient photocatalysts.